This invention deals with the problem of assembling a metallic band onto the outer surface of a cylindrical metal structure. The metals may be similar or dissimilar. This problem is commonly encountered in the manufacture of munitions where a gilding metal rotating band must be attached to the projectile casing at a specific location.
Heretofore only three methods existed for assembling copper, brass, gilding metal or sintered metal rotating bands to projectiles. These methods were: (1) pressing the band radially into a band seat with a special multi-jaw press, (2) continuous overlay welding of the heliarc or plasma arc types, and (3) swaging with a special press through a special swage die. Problems existed with methods (1) and (3) on thin-wall projectiles. Primarily, sidewall collapse occurred too frequently and secondarily the rotating bands were discarded when subjected to higher than normal ballistic stresses extant in the Army's new gun/propellant systems. Method (2) provided a ballistically sound structure but is a very slow manufacturing process. A faster, more economical means was required to assemble rotating bands onto projectile casings.
Earlier attempts at inertial welding of rotating bands had failed. In one method, the band was placed on the projectile casing and restrained from axial displacement by a spacer. This assembly was fixed in a tailstock. A high speed rotating tapered sleeve or collet was then forced onto the band to effect the weld. This method was found inadequate for several reasons, chief among those were: (1) the gilding metal on the rotating band often showed a tendency to be squirted ahead of the taper of the collet and (2) the band edge on the high side of the taper often did not become bonded to the projectile casing because there was not sufficient force available to compress the band evenly across its width.